Shoe sewing machine needle



Oct. 27, 1953 F. c. EASTMAN SHOE SEWING MACHINE NEEDLE Filed Nov. 17,1950 Inventor I I EL g F 96 F15 F198 F 9 Patented Oct. 27, 1953 UNITED-STATES PATENT. OFFICE SHOESEWING MACHINE "NEEDLE Fred: 0.. Eastmam,Marblehead, .Mass assignor to- U te S o v laq ll e (ionn a om i m stonN. J... a corporation. of New Jersey ApplicationNovember 17, 1950,S'erialNm 1 963162 3 Claims. (01. 112-222) The present invention;relates to curved hook shoe sewing machineneedles for inserting chainstitch meams and is hereinafter illustrated in the typeot needleemployed with shoeinseamlsewing machines.

The-needle in a. shoe inseam sewing machine not only acts to .drawloopsfiof sewing thread through i the work but also to perform; the.principal function in enchaining each loop with; a successive loop of:thread. each stitchandan important function initightening; and settingleach stitch in the substance. ofxthe. work. The work pieces operateduponvby a-shoe inseanrsewing machine needleare composed ofrelatively:heavy leather temporarily held: together by metallic staples insertedslightly above the. line along which the inseam lSJtOmbBu sewed. Inperforming its functions the needle frequently contacts a stapleandissubject tosuddenlstrainsiwhich are alternately reversedi along: thelength of the needle. The effects of these. strains and reversals are toimpart shock loads to a-degreewhichoften causes failure from fatigue inthe needle itself. Such failure may result inabreakageorinzpermanentdeformationof the needle toisuchan extent thatgstitcheswillhbe formed and set improperly and the thread broken Slightdeformation of the needle may not readily be perceived by an operatorwhomay be lead by threadbreakage to attempt various readjustmentsin:.the machine so I as to bring the machine intoa condition of seriousmaladjustment; In some instances, needles with poorly constructedithreadengaging surfaces may cause the same results whicha-machineoperator may fail to recognize without the use of specially designedgages.

The objects of the invention are l to providea chainstitch shoe sewingmachine needle with a configuration in its thread engaging surfaceswhich-will eliminate many of theoonditions ,above.

noted,- both from use and in the original construction of such needleand to provide a. needle ofthe type referred to which will have manytimes the durability of prior needles-of similar nature and which" willbe uniformlyelf'ective in.

forming seams with heavier tensions and w-ith lesslikelihood-of damagetothe thread employed.

The curved hook, chain stitch shoe" inseam sewing machine needle of thepresent invention comprises'a stem of uniform circular cross-section;the hook of whichopensintothe stem. at that side of a-planedefined'bytheheedle curvature away from whichwtheuwork operated. upon is-tobefed, a sharpenedpointcenteredaboutathe solid section of thelstemr of"the. needlew,oppos ite.-

the hook. and two thread guiding. rooves between the hook; and thepoint, t gmoves be,- ing cult; [to uniform depths throughout. theirlengths within the confines of the projected circular surface of theneedle stem, These-grooves are identified. as a curved side groove astraight inner groove, the latter being formed Wi h n the curvatureofthe needlelandthe former din from outs e he needle cu v u t them id tere t In the needle of the invention, unifor ndepth ofithread groovesthroughout theirlengths within the confines of the projected areapf the.circular needle stem section has been rendered. possible only by the useof a. ointcen erfid about the reduced solid section .of the stemopposite. the needle hook. When. the point iscentered about the stem ofthe. needle as a whole rather than about the reduced solid section,tapering. the needle ltowar istthepoint. causes removal ofl'material atthat. side .of the needle opposite the hook, the curvedthread guidingroove being out along sa d d o t n ed e- In cr ier'to f rm t curved.side, groove with a uniform Bfiective depth. in prior needlesto receivethe full diameter of threadintended to be employed with the ne e t e ute f he curved" roo .i e tc toward "the threadrurming from thestraight-innengroove so. that it. brings the outside thread exten ng: tr ugh the cu ed si e ov in inter e n e w ht e hr a unn n f m th s raighn e groove. By cen e he oin about the reduced. section of the stemopposite the hook, material. is provided at the point": of the needlefor ivin he curved side groove: a uniform depththroughout its lengthat'the same time it ispossible to form the outle tyofthe curvedgrooveclearof. the thread running through the straight groove. Astructural? advantage in the way orincreased strength also isobtainedflin b ng he'ne l p in i t the li e i h th reduced sectionvofthe stem opposite the hook. Inlthis .way, theforceofpenetrating thev,wnrljzoperated upon subjects. the reduced. section of the nee e morear yu e o e sion ra h than .to excessive bending force about thereduced section as. in prior needles. The use of the curved grooveofuniform depth throughout itslength is of furtherassistance inf rmingeachstitch in thatit insures retaining. each loop .on .the needle after theneedle is retracted from the and in that it renderscentaln the proper.enchainment of that loop withthe succeeding one w han d asainre et e-thewM These it and t er fe ure and d a a es of 3 the invention ashereinafter described and claimed are particularly applicable to shoeinseam sewing machine needles having fiat or duck bill type points andwill be apparent from the following detailed specification of apreferred form of needle and of its manner of use in such machine, takenin connection with the accompanying drawings, in which:

Fig. 1 is a perspective view on an enlarged scale showing some of theparts of a chain stitch shoe sewing machine in its usual manner ofoperation ona section of a Goodyear welt shoe;

Fig. 2 is a sectional view of a shoe and a novel form of needleconstructed according to the present invention, on a somewhat furtherenlarged scale, showing the position of the needle while its threadedhook is being retracted from the shoe;

Fig. 3 is a similar sectional view of a shoe with a prior needle;

Fig. 4 is a plan View of the hooked end of a prior needle showing onemanner in which the threads may lie while being retracted from the work;

Fig. 5 is a similar plan of a prior needle showing another manner inwhich the threads may lie;

Fig. 6 is a detail plan as viewed from within its curvature of a priorneedle hooked end;

Fig. '7 is a similar plan of the improved needle of the presentinvention;

Fig. 8 is a view of the improved needle showing its right side;

Fig. 9 is a bottom plan of the needle lookin from outside its curvature;and

Fig. 10 is a sectional end View of the improved needle on a stillfurther enlarged scale taken as the threaded hook is being retractedfrom the work.

The operating devices of the shoe inseam sewing machine illustrated inthe drawings are a curved hook needle l2, a needle looper l4 and athread finger 16 arranged and actuated in the usual manner to form achain stitch inseam for securing together a welt l8, a lasted upper 20and the upstanding rib 22 of an insole 24, the shoe parts being mountedupon a supporting last 26. The illustrated needle has a stem of uniformcircular cross-section and is curved in the arc of a circle along itslength with a hook opening at one side of the plane defined by theneedle curvature. To insert the inseam the needle l2 pierces the shoeparts, entering and emerg ng without engaging the supporting last 26 andwith the chain of the seam engaging the welt. After penetrating the shoeparts the sewing thread is laid in the hook of the needle by movement ofthe looper l4 about the projecting end of the needle in a clockwisedirection, facing the needle point. To provide thread for the needle, asthe needle retracts from the work with the thread, the thread is firstengaged with the thread finger l6 before the looping operation. Thethread finger then holds aside a measured length of thread between thelast formed stitch and the looper and the measured length is given up asthe threaded needle hook retracts through the work.

Before entry of the thread into the needle hook the thread actually isfirst engaged with the needle stem somewhat above the hook from outsidethe needle curvature and then is wrapped upwardly, first entering theouter side of the hook,

which hook is disposed on the left-hand side of the needle stem, withthe completed stitches of a seam. The opening into the hook faces thatside of the needle away from which the work operated upon is to be fed.As the needle begins to retract from the work the thread carried by itshook is engaged by the outer surfaces of the work around the needleopening. The portion of thread first engaged by the needle is thenpushed toward the point of the needle and the length of thread runningto the looper from inside the hook moves toward a position of parallelrelation along the needle inside its curvature. When the threaded hookhas entered the work the thread engaged thereby begins to form a loop,the inside length of which lies along a short straight inner guidinggroove 28, running from the hook toward the point along the inside ofthe needle curvature. Outside the curvature of the needle the threadportion first engaged by the needle forms the outside length and entersa curved outside thread guiding groove 30 extending substantially 180degrees around the stem of the needle from the outside of the hooktoward the point in a counterclockwise direction facing the needlepoint. The purpose of the curved side groove is to bring the outsidethread length eventually from the hook outside the needle curvaturearound the right side of the needle and over the point of the needleinto a position inside and across the needle point, as illustrated inFig. 1.

In Fig. 1 the threaded needle is illustrated as being fully retracted.from the work in the dotdash position. The full line positionillustrates the relationship oi the two thread lengths of a needle loopmore clearly, the outside length 32 of the loop being connected with thepreviously formed stitch and the inside length 34 running from theinside of the needle hook to the supply through the looper M. In thepreviously formed stitch, the illustration of which enables a betterunderstanding of the relationship of these thread lengths, the outsidelength 36 extends to the previously formed stitch and corresponds to thelength 34 in the stitch being formed, while the inside length 33 didextend to the supply before the loop 32, 34 was formed. It will thus beseen that with the loops of thread lying snugly against the welt (8 theinherent nature of a chain stitch seam causes a twist to be imparted tothe threads inside the material of the work, the threads on the chainside being located naturally in side-by-side relationship crosswise ofthe seam and the threads along the channel between the rib 22 and theinsole 24 being located in side-by-side relationship along the seam. Itis this 90 twist in the threads together with unavoidable inaccuraciesin control of the thread by the stitch forming devices which frequentlycauses irregularities in formation of stitches and in the resultingseam.

A prior art needle, such as shown at l2 in Figs. 4, 5 and 6 for sewingshoe inseams is formed with a so called duck bill point in which achisel. shape is provided, the widest dimension along the cutting edgeof which extends along the line of the seam to be inserted. However, toprovide good penetration of the needle the duck bill tapers toward itscutting edge, the side edges being inclined together toward the pointwith the result that the curved side groove 30 connecting the outside ofthe needle hook is of such reduced depth at its outlet where itintersects the relatively fiat inside surface of the duck .bill pointthat there is insufiicient ability to hold the thread reliably in placein the straight groove 28. An attempt to increase the depth of the.needlemay comeso.closetoastaplc tha side thread .32 is frayedorgsevered at the cross- 15 .curved' rooye, outlet will not mnroye thcondition since the thread; will: n t be pressed. 11 1 it by engagementwith the sufiiciently for reliable results an ifthe grooyeiswincr ascddepth it will promote a further difiicnlty hrou interference with thethread, len th 3.4;. .If-the outlet of the curved groove 3.0- isdeepened; or the outside length 3.2 of thread. (see Fig, .4.) i held inplace from other cause itmay be ledtaemerge from. the outlet or thecurvederooyotfl' tlth inside. duck bill surface too close to the insidlength 34 a d the outsideleneth 321; may overliethe inside. len th 3.4-.as illustrated. Ei When thisv occurs. the: ClT Q-I etween th threadsbulges and ompressc th thr ad-fiber sufiiciently to impede ret a t onof. the needle. To reduce these condit' s the inside groove. 21% hasalways been terminated between the .hOQk and the outlet f- .th urved.roove 3.1 hu incre sin th pre sure of he wmkon t ezthn a length 34 sothat it will be held; line with. a certa n. de r e of. flexibi i y op itth ou l of the curved groove 352,;

Frequently when the upper andthe insole rib of ashoe are temporaril atached by means o metallic staples, as illustrated atfill, thepriorartheoutover along the insi e surface of. th uck ill while theneedle-is-beihs retracted, as indicated in Fi .3, the already compress doutsid th ea length 32 being jammed with heavy pressure beneath thecorner. of thestaple.

If the threads do not crossover on h insid surfaceof theduck; bill aheadof the needle point they may be pressed into a side-by-side relationshipduring their passage through the material of the work. In such casetheinside length 34' may press the outside length 32' out of the outletto the curved side groove 30, asshown in Fig. 5. I

If this. occurs the outside length 31' of thethread may slip outwardly.past the needle point, indicated at 42, as the point is being retracted.In this case, when the work isfed relatively to the needle 12', from theposition indicated by the dot-dash u e, mi e-. ith nd cat in solid linesthe thread will not be retained in the curved side groove 30'. As aresult, the loop will be freed from the needle hook during thesucceeding work penetrating stroke and will not be enchained with thesucceeding needle loop.

To avoid both the possibility of causing the lengths of each needle loopfrom crossing over each other as in Fig. 4 or the inside length 34 frompressing the outside length 32' out of the outlet of the side groove 30'as in Fig. and to insure that both lengths of thread in each needle loopwill lie uniforml in side-by-side relationship under all conditionsalong the inner surface of a duck billed needle point, according to afeature of the present invention, the right side of the improved needleI2 opposite the opening in the hook or that side facing the directiontoward which the Work is fed forms a continuation of the needle stemsurface substantially to the point of the needle with a dimensioncorresponding to the full diameter of the needle stem sectional area,there being no perceptible set-back along th edge of the duck bill point42 at this side of the needle. To insure proper penetration of theneedle point, however, the opposite edge of the duck bill point belowthe hook of the needle is formed with a gradual setback from a locationabout halfway between the hook and the extreme tip of the point. Thecurved side groove 30 is o the formed a uniiqrm y' ample area and d athrequ d. f e fu l. iamet r oflar est, h ead intend d. orbe emnloyed fromth ope n oi th ho k outsi e. t ez urrature, o the needle. throushoutitsen th aits ou et th k bill. noin ins de the needle curvature. Theresult, th 1 he: r ht side o thc-znccdle reni thezstem. to duck llpointlics ta ent to a sin le plane the; threaded n ed e wit drawn om thew rk. h Outside t d ens 3:2 isa-forc d bosit re ytbelowt esuriaceofeneedle, by inner Wa of; the p rfo ati n. the workh o en a emen withthcurved aid isrooye 341; m l: s r tai edim thi vg oye dur n ret actingmoyem nttbraue the wor by hec osesfit .ns. nner wallet perior tion. Wththe prior eed e .l-. ":-f rrn dvwith a-set ack ht ed -1 alonmin-.tqto. proy xi a taper t e usual w he ot- -h work ns de the pe fortion on the out et curved oye 3.0 eliev d as they po nt retr c s s thatther isu o pos t-lye. oldin powe to et in t threadin the out et of; theroove 38; hcaselit i pre e ou wardly. by e t ca .ho o r g i o a locationub an all ope i he ut e 'o he cu ds oove; 3. (Fig. 7') with ut er in eout t Len then ng th ins de gr ove 8.- en bles hise c e al o, w c ha hee of r be lie med; v h shallow, di ens on. o nsulin. for f ll: d am terQf" hehre demployedwit a. given needle, now to be out with a uniformlyample sectional area and depth throughout its length for the fulldiameter of thread employed between the bottom of the groove and theconfines of the projected cylindrical surface of the stem so that duringretraction of the threaded needle from the work the inside length 34 ofthe loop will be protected by 'the upstanding sides of the inside groovefrom abrasive contact with staples or other interferences. The effect ofa full depth groove 28 to prevent abrasive contact of the thread lengths32 or 34 with staples is clearly illustrated in Fig. 10.

From the above described construction it is apparent that anadvantageous chain stitch shoe sewing machine curved hook needle isprovided, having thread guiding grooves extending from its hook towardits point with uniformly full sectional areas and depths throughouttheir lengths between the bottoms of the grooves and theprojected-surfaces of the needle stem but that the point itself islocated to impart the greatest possible strength to the needle.Referring more particularly to Fig. '7 the point 42 is centered aboutthe dot-dash line 44 which represents the center of the solid needlesection opposite the opening of the hook. Accordingly, duringpenetration of the work the forces reacting on the needle will becentered about this line. For this reason no substantial bending forcesare imparted to the needle at the hook, this section being the weakestpart of the needle. Also, during retraction of the needle the threadlengths 32 and 34 are located positively inside the needle point, asillustrated in Fig. 10, so that the tension on the thread is exertedmore nearly in line with the center 44 of the solid needle section alongits weakest area opposite the hook.

The nature and scope of the invention having been indicated what isclaimed is:

1. A chain stitch shoe sewing machine needle comprising a stem ofuniform circular cross section curved in the arc of a circle andprovided with a hook opening to one side of a plane defined by theneedle curvature, the opening in which faces the completed stitches inthe seam inserted thereby, the stem having straight and curved threadguiding grooves extending from opposite sides of the opening in the hookand along the stem to direct the two thread lengths running from a loopcarried by the needle into side-byside relation within the confines ofthe projected surface of the stem and a point sharpened to a duck billwith the widest dimension extending along the line of the seam insertedthereby and centered about the section of the needle stem opposite thehook, the curved groove intersecting the surface of the duck bill alongthe widest dimension to form an outlet of ample sectional area requiredfor the full diameter of thread employed with the needle and thestraight groove extending toward the point of the needle to a locationopposite the outlet of the curved groove without intersecting saidoutlet.

2. A chain stitch shoe sewing machine needle comprising a stem ofuniform circular cross section curved in the arc of a circle andprovided with a hook opening to one side of a plane defined by theneedle curvature and facing the completed stitches in a seam inserted bythe needle, said stem having straight and curved thread guiding groovesextending from the needle hook inside and outside of the needlecurvature to direct both thread lengths extending from a loop whileengaging the needle into side by side relation inside the curvature ofthe needle and a sharpened point centered about the solid section of theneedle stem opposite the hook, said curved groove extending from thehook opening outside the curvature of the needle to an outlet inside theneedle curvature and being of a uniformly ample sectional area and depththroughout its length required for the full diameter of thread employedwith the needle.

3. A chain stitch shoe sewing machine needle comprising a stem ofuniform circular cross section curved in the arc of a circle andprovided with a hook opening to one side of a plane defined by theneedle curvature and facing the completed stitches in a seam inserted bythe needle, said stem having thread guiding grooves located to directboth thread lengths extending from a loop while engaging the needle intoside by side relation inside the curvature of the needle and a pointsharpened to a duck bill with the Widest dimension extending along theline of the seam inserted and centered about that section of the needleopposite the opening in the hook, the thread guiding grooves extendingfrom opposite sides of the needle hook and one of the grooves extendingfrom the outside of the hook around the needle to a point ofintersection with the inner surface of the duck bill to form an outletof ample sectional area and depth required for the full diameter ofthread employed with the needle, the outlet for said last-mentionedgroove being located along the length of the needle opposite the otherthread guiding groove without intersecting said other thread guidinggroove.

FRED C. EASTMAN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 211,242 Lascell Jan. '7, 1879 947,485 French Jan. 25, 19102,097,495 Lineham et al. Nov. 2, 1937 FOREIGN PATENTS Number CountryDate 15,659 Great Britain Nov. 2, 1916

